WinAPI 字符及字符串函数(3): CharUpper - 字符或字符串转大写
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
Button3: TButton;
Button4: TButton;
Button5: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
procedure Button5Click(Sender: TObject);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

{对字符}
procedure TForm1.Button1Click(Sender: TObject);
var
C: Char;
begin
C := 'a';
C := Char(CharUpper(PChar(C)));
ShowMessage(C); {A}
end;

{对字符常量}
procedure TForm1.Button2Click(Sender: TObject);
var
C: Char;
begin
C := Char(CharUpper(PChar('a')));
ShowMessage(C); {A}
end;

{对字符数组}
procedure TForm1.Button3Click(Sender: TObject);
var
Arr: array[0..2+1] of Char;
begin
Arr := 'abc';
CharUpper(Arr);
ShowMessage(Arr); {ABC}
end;

{对字符串}
procedure TForm1.Button4Click(Sender: TObject);
var
str: string;
begin
str := 'abc';
CharUpper(@str[1]);
ShowMessage(str); {ABC}
end;

{Delphi 的 System.UpCase 和 SysUtils.LowerCase}
procedure TForm1.Button5Click(Sender: TObject);
var
c: Char;
str: string;
begin
c := 'a';
c := UpCase(c);

str := 'abc';
str := UpperCase(str);

ShowMessageFmt('%s, %s', [c, str]); {A, ABC}
end;

end.